Process for forming hollow forgings.



E. H. STEEDMAN.

Patented Jan. 9, 1917.

EDWIN H. STEEDMAN, OF ST. LOUIS, MISSOURI.

PROCESS FOB FOBMING HOLLOW FOBGINGS.

Bpeoilcation of )Setters Iatent.

Patented Jan. 9, 1917.

Application filed Iarch 31, 1916. Serial No. 88,054.

To all whom t may concern Be itknown that I, EDWIN H. STEEDMAN, acitizen of the United States, residing at St. Louis, Missouri, haveinvented a certain new and useful Improvement in Processes for FormingJHollow Forgings, ofv which the following is a full, clear, and exactdescription, such 'as will enable others skilled. in the art to which itappertains tomake and use the same. v

This invention relates to a novel 4process for making hollow forgings.

Heretofore it was practically impossible to produce uniformly accuratefergings in making hollow forgings by piercing a hole or cavity in abillet or metal blank, on account of the tendency of the piercing punchto deflect from a straight line when operating on some billets or to beimproperly po| sitioned with relation to the outer surface of theforgings when operating on other billets. One method that has been triedt0 overcome the objections above referred to is to arrange a guideadjacent the open end of the die, so as to try to start the piercingpunch at the center of the die, but commercially this is not possible,on account of the piercing punch becoming very hot when in use and onaccount of the fact that it is not possible to make a 'guide thatWillcompensate for the rapid wear en the end 'of the piercing punch, andthus guide the piercing punch accurately after it has been in use for ashort time. Even 'when such a guide is used the irregular shape of theend of the piercing punch bearing on the 'end 'of the billet has ltendencyl to force the punch laterally during the first few inches ofits travel through the billet. This, ofcourse, springs the piercingpunch out 'of true axial alinement with the die. and as the punch entersfarther into the billet, the spring or deflection greatly increases,frequently resulting in bending the piercing punch. As the billet isusually merely dropped into the die and not compressed prior to thepiercing operation, there are voids between the outer surface of thebillet'and' the inner surface of the die. Consequently, even though thepiercing 'punch is accurately guided, a 'thing that is not possible commercially, the unequal resistance caused by the voids on the side of thedie cause the punch to travel out of axial alinement with the 'die essoon as it enters the billet to a reasonable extent.

The main'object of my invention is to provide a metal forging processthat will insure the production of uniformly accurate hollow forgingshaving cavities or center openings that are accurately alined andproperly positioned.

Another object is toprovide a process for making hollow forgings whichmakes it possible to use a billet ormetal blank of irregular form thatdoes not even approximately fit the die, or a billet or metal blank inwhich the end operated upon by the piercing punch is irregular in shape,such as a sheared billet whose end yhas not been squared after comingfrom the rolls. To this end I have deviseda metal forging process inwhich the billet or blank being operated on is subjected to suchtreatment prior to the piercing operation that it will accuratelyposition and guide the piercing punch that forms the cavity or centeropening in the billet.

Brietiy described, my process consists in compressing a heated 4billetor metal blank and forming a depressionin said compressed portion,either in one operation or in successive operations, and thereafterforming 'a cavity, hole or opening in the billet by means of a piercingpunch, or other suitable member which is guided by the metal surroundingthe depression in the compressed portion4 of the billet, the outersurface of the billet being preferably shaped simultaneously with theoperation of forming the cavity in same. Any suitable apparatus may beused in practicing my process, and while I have herein illustrated myprocess `used for making a hollow forging provided with a closed e'nd, Iwish it to be understood thatmy invention is applicable -to a forgingprocess in which a hole is punched through a billet, so as to form atubular-shaped article.

Figure 1 of the 'drawings is a vertical sectional view of an apparatusthat may be used in practising m process to compress the billet or blankan form a depression in the compressed portion of same, showing thebillet prior to the compressing operation. Fig. 2 is a verticalsectional view of said apparatus, showing the billet after it hascompressed and provided with a depression, the plunger in `saidapparatus bein guided by -a member arranged adjacent" e open end ofthedie. `Fi 3 is a vertical sectional view, illustrating t e piercing punchenten ing the depression in the billet, preparatory to the operation offorming the cavity in the billet; and Fig. 4 is a sectional view,illustrating the billet after the piercing op: eration has beencompleted.

Referring to the drawin s, 1 deslgnates the billet or metal blank romwhich the article is to be formed. Said billet is arranged in a die. Awhile in a heated condition. the billet being so shaped and proportionedthat it can be dropped into the die A easily, even though the. outersurface of the billet is irregular and has slight projections thereon.Thereafter, the billet is compressed and a depression is formed in saidcompressed portion hy means of a forming plunger B provided with aprojection B that is arranged or accurately guided in longitudinalalxnement with the center axis of the die A, so that the cavity orcenter opening in the completed article will be concentric with theIouter surface of the article, the projection B of the forming plungerpreferably being of substantially conical Shape, although it might becylindrical, square, or of any deA sired shape without departing fromthe spirit of my invention. The die A conforms to the shape of the outersurface of the article being formed, and when the forming plunger B actson the billet, as shown in Fig. Q, it forms a depression 2 in the upperend of the billet. distorts the metal in the billet and forces the metalin the upper end portion of the billet laterally toward the side wallsof the die A, causing the billet to fill the die suliiciently to oll'eran equal resistance en all sides to the piercing punch or member used inthe succeeding operation. While I prefer to form a depression in thebillet and compress the metal into the die to the desired extent in oneoperation, it will, of course, be obvious that the billet could becompressed and a depression formed in said compressed portion by twoseparate and distinct operations. The forming plunger B is guidedaccurately, either by the upper end portion of the die A, or by asuitable guiding member A', shown at Fig. 2, arranged adjacent the openend of the die A, so as to prevent said forming plunger from beingforced sidewise when it strikes a. billet with an irregular upper end,as shown in Fig. l, it beingr an easy matter to secure a good mechanicalguide for the forming plunger B, on account of the fact that saidplunger does not become heated to any appreciable extent and because thelarge lat eral surface of the plunger can he readily lubricated.

The final step in the forging operation consists in forming a cavity orhole in the billet and distortin the metal sufficiently to cause theouter su ace of the billet to con form accuratelyY to the shape of thedie A, this final step being preferably effected by a piercing punch ormember C which is forced into the metal contained by the die A after theforming plunger B has been withdrawn. When the piercing punch C movestoward the die A, the end of said punch, which is tapered orsubstantially conical-shaped, enters the depression 2 in the upper endof the billet, thus causing the punch C to be centered accurately withrelation to the die A. In view of the fact that the metal in the upperend portion of the billet is compressed until it practically fills theupper portion of the die A and is of substantially equal densitysurrounding the depreion Q, the uplper end portion of the billet willoler su cient resistance on all sides to the punch C, to hold said punchstraight when it starts to dlstortthe metal in the billet. As the punchC continues to more through the billet, it is held perfectly straightand is prevented from deflecting from a straight line by means of thecompressed metal surrounding the depression 2 in the billet and by themetal that is compressed progressively and equally as the punch (ltravels through the billet. The result is that the completed forgingwill be commercially accurate, as the metal is distributed evenlythroughout all portions of same, and the center cavity is concentricwith the outside of the forging.

As previously stated, any suitable apparatas may be used in practisingmy process, and while I have referred to the forming plunger B and thepunch C as being moved toward the die A, it wili of course be obviousthat the die in which the billet is arranged could he moved withrelation to the members that act upon the billet.

The process above described makes it possible to produce hollow forgingsof uniform shape and size in which the center openings are accuratelyformed and in which the metal in all portions of the side walls of eacharticle is of uniform density.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is:

1. A process for forming a hollow forging, characterized by forming adepression or recess in a billet. and also compressing the metalsurrounding said depression prior td the operation of forming a cavityor center opening in the billet.

2. A process for forming a hollow forging, characterized by forming adepression or recess in a billet and also subjecting the billet tolongitudinal pressure in a die so as to compress the metal surroundingsaid depression in the billet and thus cause the metal to substantiallyfill the adjacent portion of the die, prior to the operation of forminga cavity or center opening in the billet. i

3. A process for forming a hollow article,

which consists in compressing a billet or metal blank in a die and alsosimultaneously forming a depression in said billet by a` member thatexerts longitudinal pressure on the billet, and thereafter forming acavity or opening in the billet by means of a member that is centered bythe depression in the billet and guided by the compressed metal in thebillet that surrounds said depression.

4. A process for formingr a hollow forging, which consists in forming adepression in a heated billet or metal blank and also compressing themetal around said depression so that it is of substantially uniformdensity, and thereafter forging said billet into the shape of a hollowarticle by a mem ber that enters the depression formed in the billetduring the first part of the forging operation.

5. A process for forming a hollow forging, which consists in forming adepression in a heated billet arranged in a die and also compressing thebillet so as to fill the die to the desired extent around saiddepression,

and thereafter forging said billet into a hollow article by a memberthat enters the depression in the billet during the first part of theforging operation;

6. A process for forming a hollow forging, which consists in arranging abillet or metalblank in a die, subjecting the billet to endwise pressureso as to compress one end portion of same forming a depression in thecompressed portion of said billet concentric with the side walls of saiddie, and thereafter forming a cavity or center opening in the billet ina single operation by means of a piercing punch that is centered andguided by the depression in the billet.

7. A process for forming a hollow forging, which consists in compressina billet or metal blank in a die and also orming a depression in saidbillet concentric with the side walls of said die, and thereafterforming a cavity or center opening in the billet by means of a piercingpunch that is centered by said depression and guided by the metal in thebillet surrounding said depression.

8. A process for forming a hollow forging, characterized by compressinga billet or metal blank in a die and also simultaneously forming adepression in said billet concentric with the side walls of said die,the billet being compressed to a sufficient extent so that when thepiercing punch used in the subsequent operation is started into saiddepression a substantially equal resistance will be offered on all sidesto the piercing punch while it is traveling through the billet to formthe center opening or cavity in the billet.

In testimony whereof I hereunto aflix my signature in the presence oftwo witnesses, this twenty-eighth da of March, 1916.

DWI H. STEEDMAN.

Witnesses:

W. A. YAEGER, A. P. Fox.

